add createOpencodeServer to js sdk and wait for readiness. always use random port for opencode serve. add /client and /server imports for js sdk

packages/opencode/src/cli/cmd/serve.ts

@@ -11,7 +11,7 @@ export const ServeCommand = cmd({
         alias: ["p"],
         type: "number",
         describe: "port to listen on",
-        default: 4096,
+        default: 0,
       })
       .option("hostname", {
         alias: ["h"],